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Dispersive sensing of electron tunneling between quantum dots in proximitized InAs nanowires

ORAL

Abstract

Dispersive gate sensing (DGS) is a powerful technique that has enabled novel ways for probing condensed matter systems and reading out solid-state quantum bits, such as Josephson or spin qubits. DGS has also been proposed for the measurement of topological qubits based on Majorana zero-modes (MZMs). Such a measurement can be realized by detecting parity-dependent electron tunneling through a superconducting island hosting MZMs at its ends.
Here, we demonstrate tunneling between two quantum dots separated by a superconducting island realized in an InAs nanowire, partially proximitized by Al. Using multiplexed coplanar waveguide resonators with tailored circuit parameters we can simultaneously detect tunneling between multiple quantum dots with high SNR to correlate tunneling events with sub-microsecond resolution. The resonator response depends -via the tunneling rate between the quantum dots- on the superconducting spectrum, and in particular on the presence of MZMs in the island. Importantly, dispersive readout allows the system to be probed in the floating regime without transport channels. This will be crucial for fast, non-invasive detection of the topological state of superconducting islands and parity readout of topological qubits.

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Presenters

  • Damaz De Jong

    QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft University of Technology

Authors

  • Damaz De Jong

    QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft University of Technology

  • Daan Waardenburg

    Delft University of Technology

  • Nejc Blaznik

    Utrecht University

  • Lin Han

    Delft University of Technology

  • Filip Malinowski

    Delft University of Technology

  • Christian Prosko

    Delft University of Technology

  • Jasper Van Veen

    Delft University of Technology

  • Peter Krogstrup

    Microsoft Quantum Materials Lab and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Kanalvej 7, 2800 Kongens Lyngby, Denmark, Microsoft, Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen and Microsoft Quantum Materials Lab Copenhagen, Quantum Materials Lab Copenhagen, Microsoft, Center for Quantum Devices and Microsoft Quantum Lab–Copenhagen, Center for Quantum Devices and Microsoft Quantum Lab Copenhagen, Niels Bohr Institute, University of Copenhagen, Microsoft Corp

  • Leo P Kouwenhoven

    Dept. of Physics, Technical University, Delft, The Netherlands, Microsoft Quantum Lab Delft, Microsoft Quantum Lab Delft, Delft University of Technology, Microsoft Corp Delft, Quantum Lab Delft, Microsoft, Delft University of Technology, QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Microsoft Corp

  • Wolfgang Pfaff

    Quantum Lab Delft, Microsoft, Microsoft Quantum Lab Delft, Delft University of Technology, Microsoft Corp